A little after 11.30 yesterday morning, a Boeing 747 running on jet fuel and the oil from 150,000 coconuts parted company with the runway at Heathrow and slipped into a hazy blue sky.

Forty minutes later, the first commercial aircraft to be powered partly by biofuel touched down at Schiphol airport in Amsterdam, paving the way for what some claim could be a revolution in environmentally responsible aviation.

The experiment was the brainchild of the Virgin Atlantic boss, Sir Richard Branson, who hailed the flight as a "historic occasion" and the first step towards using biofuels on commercial flights. Three of the 747's four tanks were filled with normal jet fuel while its fourth carried a mixture that was 80% jet fuel and 20% coconut and babassu palm oil.

"Today marks a biofuel breakthrough for the whole airline industry," Branson told a press conference held next to the aircraft in a Heathrow hangar. "Virgin Atlantic, and its partners, are proving that you can find an alternative to traditional jet fuel and fly a plane on new technology, such as sustainable biofuel."

Branson has pledged to invest profits from his transport empire in biofuel production, but serious doubts have already been raised. Critics argue that biofuels damage developing countries by driving up food prices and harm the environment by encouraging deforestation.

The Heathrow trial, in partnership with Boeing, engine maker General Electric, and Imperium Renewables, attempted to assuage those concerns by using biofuel made from coconut oil harvested from existing plantations in the Philippines and oil from babassu palms, which grow wild in Brazil.

However, Branson admitted that the biofuel mix that partially powered yesterday's flight would not be used commercially.

Wild ideas

Land given to coconut plantations would have to be vastly expanded to satisfy the demands of aviation, resulting in deforestation, while the babassu palms used in yesterday's experiment are not available in sufficient numbers.

The airline industry, he added, would probably have to turn to algae in its search for viable biofuels. Algae are grown in ponds rather than on land, so they do not require deforestation or take space that could be used for food crops.

Branson said: "This pioneering flight will enable those of us who are serious about reducing our carbon emissions to go on developing the fuels of the future, fuels which will power our aircraft in the years ahead through sustainable next-generation oils, such as algae."

Environmental groups have warned that processing algae may produce more carbon dioxide than is saved by using it as an alternative fuel. There are also concerns that algae will compete for fresh-water sources as the ponds evaporate and have to be topped up.

Tim Jones, a policy officer at the World Development Movement, said the minimal amount of biofuel used in the trial underlined the difficulty of reducing emissions within the aviation industry. "It only reduces carbon dioxide emissions by 20% and there is no technology available that allows us to fly without making emissions."

Kenneth Richter, Friends of the Earth aviation campaigner, said: "Biofuels are a major distraction in the fight against climate change. There is mounting evidence that the carbon savings from biofuels are negligible. If Virgin was really serious about reducing the aviation industry's impact on the environment it would support calls for aircraft emissions to be included in the climate change bill."

Aircraft account for 5.5% of UK carbon dioxide emissions and Virgin Atlantic is not the first aviation group to experiment with alternative fuels. Earlier this month, the jet manufacturer Airbus flew an A380 superjumbo with a mix of gas-to-liquid fuel.

A much-trumpeted biofuels trial at Virgin Trains was abandoned last year after the group lost its CrossCountry franchise. A Virgin Trains spokesman said the company was "considering" whether to launch a new trial on the West Coast route.

Concerns about biofuels have spread to mainstream transport companies including National Express, which abandoned a biofuel trial for its buses amid fears that it was causing more harm than good to the environment.

The government acknowledged those concerns last week when it ordered a review of the environmental and economic impact of biofuels.

The transport secretary, Ruth Kelly, said the government might not support an EU proposal to increase the proportion of biofuel in petrol and diesel to 10% by 2020 if the review raises serious doubts.